> This page is for version v2025-04-21.
> For other versions, use one of these documentation indexes:
> - v2026-02-09 (default): https://docs.extend.ai/2026-02-09/llms.txt
> - v2025-04-21: https://docs.extend.ai/2025-04-21/llms.txt
> - v2024-12-23: https://docs.extend.ai/2024-12-23/llms.txt

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.extend.ai/llms.txt
> Use this file to discover all available pages before exploring further.
>
> ## API version
> The current API version is `2026-02-09`, served at the site root (no version prefix in URLs).
> If this page URL contains `/2025-04-21/` or `/2024-12-23/`, you are reading an older API version.
> Prefer the current docs at https://docs.extend.ai/llms.txt unless the user explicitly needs that older version.
> Do not treat older-version pages as the source of truth for new integrations.

# Splitter Composer

> Composer can now optimize splitters automatically from eval sets, in addition to extractors and classifiers.

Composer is now available for splitters, so you can optimize them automatically from eval sets. Previously, Composer was only available for extractors and classifiers.

![](/_fern-img/e4180abcaf27e8aa658e273b1a83acb58601b36602f3ad57fb8910ea53f56599.webp)

If you're working on splitting, check out our [Splitter Benchmark](https://www.extend.ai/resources/document-splitting-benchmark) to see how we evaluate models.